Algal blue light switch control of electrical excitation in plants

Optogenetics denotes the manipulation of cellular processes by light-based biological techniques. An international research team led by the Würzburg plant scientists Rainer Hedrich, Georg Nagel and Dirk Becker has succeeded in applying this method to higher plants: Light impulses can now be used to trigger electrical excitation in plants.

"With this tool, for the first time we are able to non-invasively investigate electrically based cellular communication pathways in plants at the molecular level and ask how plants use these electrical signals to respond to extreme temperature fluctuations, herbivores or other stress factors," says Dirk Becker.

How can we simulate an electrical signal in plants that is normally triggered by stress or injury without causing unwanted side reactions?

The team tackled this challenge with the help of optogenetics. Optogenetics allows to control the electrical activity of nerve cells with light pulses, provided that nerve cell membranes were previously equipped with light-sensitive ion channels from algae, known as channelrhodopsins.

Higher plants have lost the light-sensitive ion channels of algae during evolution, explains Dirk Becker. The researchers have now succeeded in returning the channelrhodopsin genes back to the genome of the model plant Arabidopsis thaliana, whose leaf cells can be specifically excited with light and the membrane electric response can be analyzed.